body { 
    font-family: Arial; 
    line-height: 1.6; 
}

header {
    background-color: #3498db;
    color: #fff;
    padding: 1em 0;
    text-align: center;
}

header h1 {
    margin: 0;
}

header .logo {
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    user-select: none;
}

header nav a {
    color: #fff;
    text-decoration: none;
    font-size: 16px;
    font-weight: 600;
    border: 1px solid transparent;
    padding: 6px 12px;
    border-radius: 4px;
    transition: background-color 0.3s, border-color 0.3s;
}

header nav a:hover {
    background-color: rgba(255, 255, 255, 0.3);
    border-color: #fff;
} 

h2 {
    text-align: center;
}

pre {
    background: #f0f0f0;
    padding: 10px;
    border: 1px solid #ccc;
    white-space: pre-wrap;
    margin: 0 auto;
    max-width: 800px;
    font-size: 20px;
}

/* 章节内容样式 */
.chapter-content {
    margin: 20px auto;
    max-width: 800px;
    font-size: 18px;
    line-height: 1.8;
}

/* Markdown样式支持 */
.chapter-content h2 {
    color: #3498db;
    margin-top: 30px;
    margin-bottom: 15px;
    font-size: 24px;
}

.chapter-content h3 {
    color: #2980b9;
    margin-top: 25px;
    margin-bottom: 10px;
    font-size: 20px;
}

.chapter-content strong {
    font-weight: bold;
}

.chapter-content em {
    font-style: italic;
}

.chapter-content p {
    margin-bottom: 15px;
    text-indent: 2em;
}

/* HTML内容样式 */
.chapter-content a {
    color: #3498db;
    text-decoration: none;
}

.chapter-content a:hover {
    text-decoration: underline;
}

.chapter-content img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 15px auto;
    border-radius: 4px;
}

.nav {
    margin-top: 10px;
    text-align: center;
}

.nav a {
    margin: 0 5px;
    text-decoration: none;
}

.nav strong {
    margin: 0 5px;
}

.directory {
  padding: 10px;
  background: #f9f9f9;
  border-radius: 8px;
}
.directory a {
  display: block;
  padding: 5px 0;
  color: #333;
  text-decoration: none;
}
.directory a:hover {
  color: #007bff;
}

footer {
    text-align: center;
    padding: 20px;
    margin-top: 40px;
    background-color: #3498db;
    color: #fff;
    font-size: 0.9em;
}